Prevalence of complement-fixing antibodies to Mycoplasma pneumoniae in the savannah and forest belts of Nigeria.

A survey of complement-fixing antibodies to Mycoplasma pneumoniae in 1673 children (aged 5-13 years) was conducted in Nigeria. Although the antibodies were detected in 25.7% of the children from the savannah belt and 20.4% of those from the forest belt, only 8.9% and 7.4%, respectively, had titres considered high enough to protect them from infection. The geometric mean titres (GMT) tended to increase with age up to 8 years and then gradually fall. The age-specific differences in GMT were significant (F = 2.98; analysis of variance with x = 0.05) but those due to the child's sex (F = 2.49) and belt of origin (F = 2.61) were not. The results indicate that Nigeria is a highly endemic area for M. pneumoniae infection, with a large pool of susceptible children in which epidemic outbreaks could occur.

T-lymphocyte activity during prodromal and exanthem stages of measles infection.

The cell mediated immune response in the prodromal and exanthem clinical stages of measles infection was measured by the degree of T-lymphocyte activity (E-rosette) and compared with controls. Data obtained showed T-cell activity which was markedly different in the stages of measles infection under investigation.

Haemagglutination inhibition antibody levels one year after natural measles infection and vaccination.

An assessment of haemagglutination inhibition antibody (HAI) titres of 1,163 children, comprising 739 recipients of live measles vaccines and 424 patients with natural measles infection after 1 year was made in this investigation. Statistical analysis revealed a significant difference in the levels of HAI antibodies. Of the vaccinated children a significant 67.45% showed antibody titres of less than or equal to 1:16, while only 23.48% of children with natural measles showed these antibody titres. The importance and implication of such HAI antibody titres is discussed.

(Avid) rosette-forming cells as evidence for cellular immunity following measles virus vaccination in monkeys: correlation with the presence of haemagglutination inhibitory antibodies.

Lymphocytes characterized by in vitro rosette formation with sheep erythrocytes were enumerated in blood of normal and measles virus-vaccinated monkeys. Rosetting lymphocyte counts increased significantly as a result of vaccination. Concomitantly, HAI-antibody, undetectable before vaccination, became detectable, suggesting that the simple and inexpensive technique of enumerating rosetting lymphocytes can be used as an alternative to other more cumbersome and expensive methods for evaluation of development of cell-mediated immunity following measles virus vaccination.

The levels of measles antibodies in Nigerian children aged 0-12 months and its relationship with maternal parity.

Six hundred and fifty-seven children aged between 0 and 12 months were randomly chosen and studied for measles antibody titres by the haemagglutination inhibition (HAI) test. The results showed significant variations in HAI antibody titres. Children between 0-3 months showed high measles HAI antibody titres which declined to a trough between 4 and 6 months. A rise in HAI antibody titre was observed from 10 to 12 months age. Multiparity and higher age in the mothers were noted as probable factors influencing the titres of measles HAI antibody in children. The results indicated that with increased maternal parity, measles HAI antibody titres in the children declined.

Measles antibody levels in children of rural and urban areas of Nigeria following vaccination campaign.

This study compares the presence and level of measles haemagglutination inhibiting antibody in the sera of primary school children in selected rural and urban areas of Kaduna State, Nigeria following a vaccination campaign. The results, analysed by Mann-Whitney statistical test at alpha = 0.05, showed significantly higher levels of haemagglutination inhibiting antibody in all the age groups in urban areas when compared with rural areas. The implications of these findings on measles vaccination campaigns are discussed.

In vitro effect of haemagglutination inhibition antibodies on measles virus replication.

Children between the ages of 6 and 15 years were studied for the presence of serum levels of measles haemagglutination inhibition antibodies in relation to the continual measles epidemics in Nigeria. The neutralization of Edmonston B strain of live measles virus by such antibodies was also studied in Vero cells. The results indicate that in Vero cells, replication of the virus could be inhibited for up to 3 days by haemagglutination inhibition antibody at a concentration of 1:16.

Detection of a microsomal antigen and its antibody in human liver diseases.

Sera of 173 patients with various forms of liver disease along with serum precipitates produced by polyethylene glycol were screened for the presence of a microsomal antigen referred to as ubiquitous tissue antigen (UTA) and its antibody by double diffusion precipitation in agarose gel. UTA was detected in 7 or 26 patients with chronic active hepatitis, 1 of 5 with alcoholic hepatitis, 2 of 14 with alcoholic cirrhosis and 18 of 98 with hepatoma. Antibodies to UTA were found only in 2 patients with chronic active hepatitis, 1 with alcoholic cirrhosis and 1 with hepatoma. No UTA or its antibody were noted in sera of 5 patients with alcoholic fatty liver, 10 patients with hepatitis B, and 15 asymptomatic carriers of HBsAg. Positivity for the UTA or its antibody was restricted to severe, chronic cases irrespective of diagnosis, indicating that persistent tissue destruction might be necessary for antigen release or antibody formation.

Immunoglobulin levels in Nigerian cord blood sera.

We have quantified the levels of IgG, IgA and IgM in Nigerian cord blood samples during the dry and the wet seasons. Almost all the samples collected during both seasons had detectable levels of IgG and IgM, while IgA was detected in 71% of those collected in the rainy season and in only 45% of those collected during the dry season. We observed seasonal variations in the levels of each of these immunoglobulins but the variations were not consistent for all three immunoglobulin classes. This suggests that the levels of each immunoglobulin class in the cord blood is probably controlled by different antigenic factors in our environment. The mean values for all three immunoglobulin classes were raised in all our samples above those of UK cord blood samples. This is consistent with earlier reports for samples collected in the tropics. In the paired cord/maternal immunoglobulin estimations, 75% of cord sera had higher levels of IgG than their corresponding maternal samples, suggesting either active transfer of the immunoglobulin across the placenta or increased rate of synthesis or decreased rate of catabolism in utero.

Serological evidence for the presence of rickettsial infections in parts of Nigeria.

Weil-Felix tests using OX19 and OXK proteus antigens reveal high antibody titers to OXK and OX19 antigens in patients reporting at the University of Nigeria Teaching Hospital, Enugu with clinical diagnosis of pyrexia of unknown origin. These findings suggest the presence of either or both scrub typhus fever and Epidemic typhus fever in this community. While the advisablility of using other diagnostic techniques to support and confirm positive Weil-Felix reaction will be useful, it is felt that the above findings are strong evidences for the prevalence of these diseases in this part of Nigeria.